The system is based on a dual delay-line oscillator configuration. The electronic circuits, consisting of two Automatic Gain Controlled (AGC) amplifiers and a mixer, are located between the two identical ZnO-Si0 -Si layered delay lines. The system can be used for many sensor applications by placing an appropriate (bio)chemical or physical interface on the propagation path of one of the delay lines [1,2]. An interaction with such an interface will cause a shift in the oscillator frequency. The other delay line is used as a reference. The two SAW oscillator frequencies are mixed and the frequency difference is the sensor output. The realization of the system on a silicon chip is discussed together with its design rules. The experimental performance with respect to stability, temperature dependence and electricalfeedthrough suppression is given. 2
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